Answer:
V1 =8.1 m/s
Explanation:
height at highest point (h2) = 4.1 m
height at lowest point (h1) = 0.8 m
acceleration due to gravity (g) = 9.8 m/s^{2}
from conservation of energy, the total energy at the lowest point will be the same as the total energy at the highest point. therefore
mgh1 + 
= mgh2 + 
where
- speed at highest point = V2
- speed at lowest point = V1
- mass of the girl and swing = m
- at the highest point, the speed is minimum (V1 = 0)
- at the lowest point the speed is maximum (V2 is the maximum speed)
- therefore the equation becomes mgh1 + = mgh2
m(gh1 + 
) = m(gh2)
gh1 + = gh2
V1 = 
now we can substitute all required values into the equation above.
V1 = 
V1 = 
V1 =8.1 m/s
We can solve the problem by using the law of conservation of energy.
Using the ground as reference point, the mechanical energy of the brick when it is at 5 m from the ground is just potential energy (because the brick is initially at rest, so it doesn't have kinetic energy):
when the brick is at h'=3 m from the ground, its mechanical energy is now sum of kinetic energy and potential energy:
where v is the velocity of the brick. Since E is conserved, it must be equal to the initial energy (98.1 J), so we can solve this equation to find v:
Which amplitude of the following longitudinal waves has the greatest energy?
amplitude = 10 cm; wavelength = 6 cm; period = 4 seconds
Answer:
B = 0.046T
Explanation:
given
size of the screen = 51.2cm
distance from center = 11.1cm
region of magnetic field = 1.00cm
V= 22000V= 22kV
Answer:
2.286 ohm
Explanation:
R1 = 16 ohm
R2 = 8 ohm
R3 = 4 ohm
They all are connected in parallel combination
Let the equivalent resistance is R.
1/R = 1/R1 + 1/R2 + 1/R3
1/R = 1/16 + 1/8 + 1/4
1/R = (1 + 2 + 4) / 16
1/R = 7 / 16
R = 16/7 = 2.286 ohm
